557. Reverse Words in a String III

Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: "Let's take LeetCode contest"
Output: "s'teL ekat edoCteeL tsetnoc"

 Note: In the string, each word is separated by single space and there will not be any extra space in the string.

题目含义：翻转每一个单词，单子之间的位置保持不变

 方法一：

    public String reverseWords(String s) {
        String[] words = s.split(" ");
        StringBuilder result = new StringBuilder();
        for (String word:words)
        {
            String newWord = new StringBuilder(word).reverse().toString();
            result.append(newWord).append(" ");
        }
        return result.toString().trim();        
    }

方法二：

public String reverseWords(String s) 
{
    char[] s1 = s.toCharArray();
    int i = 0;
    for(int j = 0; j < s1.length; j++)
    {
        if(s1[j] == ' ')
        {
            reverse(s1, i, j - 1);
            i = j + 1;
        }
    }
    reverse(s1, i, s1.length - 1);
    return new String(s1);
}

public void reverse(char[] s, int l, int r)
{
    while(l < r)
    {
        char temp = s[l];
        s[l] = s[r];
        s[r] = temp;
        l++; r--;
    }
}